Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are persistent anthropogenic compounds that are globally distributed. Human exposure to these compounds is evident worldwide, but how this occurs is not well understood due to a general lack of knowledge regarding sources, transport, and fate. Exposure within homes is likely to be particularly important since many consumer products have been treated with PFCs, and most people spend the majority of their time indoors. A cohabiting sentinel species, such as the domestic cat, may prove to be a useful indicator of potential indoor exposure routes. In this study, high-resolution mass time-of-flight mass spectroscopy (TOF) was used to quantitate PFCs in serum samples from 76 domestic cats. PFCs were found to be present in all but one serum sample with PFOS and perfluorohexane sulfonate (PFHxS) ranging from